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| United States Patent |
5,351,277
|
|
Goto
, et al.
|
September 27, 1994
|
Method of constructing top slab of nuclear reactor container and nuclear
reactor container constructed by the method
Abstract
A method of constructing the top slab of a nuclear reactor container in
which a flange for mounting the top head of the container is prepared
separately from the sleeve of the container. When the outside diameter of
the flange is greater than the inside diameter of a doughnut-shaped steel;
reinforcement structure assembled on the container, the steel
reinforcement structure is situated in place and then the flange is welded
to the sleeve, thus shortening the construction period. Disclosed also is
a nuclear reactor container constructed by this method.
| Inventors:
|
Goto; Hiroshi (Hitachi, JP);
Suzuki; Tadao (Kure, JP)
|
| Assignee:
|
Hitachi, Ltd. (Tokyo, JP)
|
| Appl. No.:
|
684981 |
| Filed:
|
April 15, 1991 |
Foreign Application Priority Data
| Current U.S. Class: |
376/293; 376/260; 376/295; 376/296 |
| Intern'l Class: |
G21C 009/00 |
| Field of Search: |
376/293,295,296
|
References Cited
U.S. Patent Documents
| 4587081 | May., 1986 | Malaval | 376/295.
|
| 4696790 | Sep., 1987 | Elter et al. | 376/296.
|
| 5119598 | Jun., 1992 | Tajiri et al. | 376/293.
|
| Foreign Patent Documents |
| 49-111420 | Oct., 1974 | JP.
| |
| 52-26714 | Feb., 1977 | JP.
| |
| 56-125691 | Oct., 1981 | JP.
| |
| 57-19696 | Feb., 1982 | JP.
| |
| 57-57289 | Apr., 1982 | JP.
| |
| 59-142496 | Aug., 1984 | JP.
| |
| 62-165185 | Jul., 1987 | JP.
| |
| 62-169082 | Jul., 1987 | JP.
| |
| 62-170885 | Jul., 1987 | JP.
| |
| 62-273347 | Nov., 1987 | JP.
| |
| 62-298794 | Dec., 1987 | JP.
| |
| 64-74498 | Mar., 1989 | JP.
| |
| 6479693 | Mar., 1989 | JP.
| |
Primary Examiner: Walsh; Donald P.
Assistant Examiner: Voss; Frederick H.
Attorney, Agent or Firm: Antonelli, Terry, Stout & Kraus
Claims
What is claimed is:
1. A method of constructing a top slab of a nuclear reactor container
having a sleeve with a flange and a prefabricated doughnut-shaped steel
reinforcement structure wherein the outermost diameter of said flange is
greater than the innermost diameter of said prefabricated doughnut-shaped
steel-reinforcement structure, comprising the steps of:
placing a container sleeve separate from said flange, at a position where
said top slab is to be constructed;
lifting said prefabricated doughnut-shaped steel reinforcement structure
and placing this structure at a position where it forms said top slab; and
welding said flange to said container sleeve for mounting a top head of
said nuclear reactor container on said flange.
2. A method according to claim 1, wherein said prefabricated
doughnut-shaped steel reinforcement structure has a cylindrical auxiliary
plate integrated therewith and located near the innermost circumference of
said prefabricated doughnut-shaped steel-reinforcement structure.
3. A method according to claim 2, wherein said welding said flange to said
container sleeve is conducted simultaneously with pouring concrete in and
solidifying the same on the outer diameter side of said cylindrical
auxiliary plate, followed by pouring concrete in and solidifying the same
on the inner diameter side of said cylindrical auxiliary plate, bounded by
said container sleeve and said cylindrical auxiliary plate.
4. A method of constructing a top slab of a nuclear reactor container
having a sleeve with a flange and a prefabricated doughnut-shaped steel
reinforcement structure wherein the outermost diameter of said flange is
greater than the innermost diameter of said prefabricated doughnut-shaped
steel reinforcement structure, comprising the steps of:
prefabricating a structure integrating a top slab liner, a container
sleeve, separate from said flange, fixed to the inner periphery of said
top slab liner substantially orthogonal to said top slab liner, and said
prefabricated doughnut-shaped steel reinforcement structure on said top
slab liner, and lifting and mounting said prefabricated doughnut-shaped
steel reinforcement structure to a position where said top slab is to be
constructed; and
welding said flange to said container sleeve for mounting a top head of
said nuclear reactor container on said flange.
5. A method according to claim 4, wherein said prefabricated
doughnut-shaped steel reinforcement structure has a cylindrical auxiliary
plate integrated therewith and located near the innermost circumference of
said prefabricated doughnut-shaped steel reinforcement structure.
6. A method according to claim 5, wherein welding said flange to the
container sleeve is conducted simultaneously with pouring concrete in and
solidifying the same on the outer diameter side of said cylindrical
auxiliary plate, followed by pouring concrete in and solidifying the same
on the inner diameter side of said cylindrical auxiliary plate, bounded by
said container sleeve and said cylindrical auxiliary plate.
7. A nuclear reactor container, comprising:
a bottom-equipped cylindrical portion for containing a nuclear reactor
therein:
a top slab provided on top of said cylindrical portion and composed of a
doughnut-shaped steel reinforcement structure and concrete placed
integrally with said doughnut-shaped steel reinforcement structure, said
top slab having a central bore;
a container sleeve outlining said central bore of said top slab; and
a flange fixed by welding to said container sleeve and said flange having
its outermost diameter greater than the innermost diameter of said
doughnut-shaped steel reinforcement structure; and
a top head attached to said flange.
8. A nuclear reactor container according to claim 7, wherein a cylindrical
auxiliary plate is integrated with said doughnut-shaped steel
reinforcement structure near the innermost circumference thereof.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of constructing the top slab of a
steel-reinforced concrete nuclear reactor container in a nuclear power
generating plant and also to a nuclear reactor container constructed by
such a method.
2. Description of the Related Art
A known construction method will be described with reference to FIG. 5
which shows the construction of a nuclear reactor container made of
steel-reinforced concrete, FIG. 6 which is an illustration of a top slab
portion of the nuclear reactor container, illustrative of the conventional
construction method and FIG. 7 which is a flow chart of the known
construction method.
The nuclear reactor container made of steel-reinforced concrete has a
bottom-equipped cylindrical portion 2, a top slab 4 and a top head 5. The
interior of the container is divided into two spaces by a diaphragm floor
3. The nuclear reactor container contains a pressure vessel 6 of a nuclear
reactor and forms a portion of a nuclear reactor house 1.
The known construction method will be described with specific reference to
FIGS. 6 and 7. After mounting a liner 11 for the cylindrical portion,
temporary posts 14 and temporary trusses 15 are installed and a top slab
liner 10 is placed on the top of the temporary trusses 15. A flanged
sleeve 7 of the nuclear reactor container is set up and welding is
conducted at the welding lines 12 and 13. Then, doughnut-shaped top slab
reinforcers 8 are assembled on the top slab liner 10. Subsequently, the
reinforcers 9 for the cylindrical portion are set up and connected to the
top slab reinforcers 8. Then, a concrete is poured and, after drying and
solidification of the concrete, the temporary posts 14 and the temporary
trusses 15 are removed.
Arts pertaining to this known construction method are: a method of
constructing a cylindrical liner (Japanese Patent Laid-Open No.
62-170885), a method in which beams are extended through a
steel-reinforced concrete top slab forming the upper structure of a
nuclear reactor core, the beams being connected to a lining (Japanese
Patent Laid-Open No. 62-165185), a non-unitizing top slab installation
method (Japanese Patent Laid-Open No. 62-169082), an art relating to liner
structure of cylindrical a portion of a reactor container (Japanese Patent
Laid-Open No. 62- 298794), and a method of laying steel reinforcers
(Japanese Patent Laid-Open No. 64-74498).
The following arts are also proposed: a hollow pre-cast slab incorporating
steel reinforcement beams and a method of producing the same (Japanese
Patent Laid-Open No. 49-111420), a method of constructing a floor using a
deck plate in place of a frame (Japanese Patent Laid-Open No. 52-26714), a
method of constructing an intermediate slab of a base structure of nuclear
2 reactor for supporting a nuclear reactor pressure vessel (Japanese
Patent Laid-Open No. 56-125691), a method in which an H-shaped steel is
attached to each side of a lining for a concrete container (Japanese
Patent Laid-Open No. 57-19696), a method in which works such as attaching
of trays with ceilings, ducts, pipes and supporting structures are to deck
beams and set-up of pipes to upper side of beams are conducted in a
factory thus unitizing ceiling deck plate (Japanese Patent Laid-Open No.
57-57289), a method of lining the side wall of a reactor container made of
steel-reinforced concrete, wherein the liner is integrated with steel
reinforcers (Japanese Patent Laid-Open No. 59-142496), a method in which
pipes to be buried in the floor of a reactor house are assembled in steel
reinforcer units (Japanese Patent Laid-Open No. 62-273347), and a method
in which steel reinforcers of a cylindrical portion of a shield wall is
assembled from a plurality of units (Japanese Patent Laid-Open No.
64-79693).
In these known arts, however, no consideration has been given to the
efficiency in constructing a nuclear reactor container having a sleeve
with a flange of an outside diameter which is greater than the inside
diameter of a doughnut-shaped steel-reinforced structure. This problem has
caused an impediment in constructing a nuclear reactor container.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a method of
constructing the top slab of a nuclear reactor container which can shorten
the period of work even when the container has a sleeve with a flange of
an outside diameter greater than the inside diameter of a doughnut-shaped
steel reinforcement structure, as well as a nuclear reactor container
constructed by such a method.
To this end, according to one aspect of the present invention, there is
provided a method of constructing the top slab of a nuclear reactor
container, comprising the steps of: placing a container sleeve without a
flange at a position where the top slab is to be constructed; lifting a
prefabricated doughnut-shaped steel reinforcement structure and placing
this structure at a position where it forms the top slab; and welding a
flange for mounting a top head of the container to the sleeve.
Preferably, the prefabricated doughnut-shaped steel reinforcement structure
has an auxiliary plate integrated therewith and located so as to face the
flange of the container after the welding of the flange.
It is also preferred that the welding of the flange and the sleeve is
conducted simultaneously with placement of concrete in the space next to
the space between the auxiliary plate and the container sleeve followed by
placement of concrete in the space defined by the auxiliary plate, the
flange and the sleeve.
The invention also provides a method of constructing the top slab of a
nuclear reactor container, comprising the steps of: prefabricating a
structure integrating a top slab liner, a container sleeve fixed to the
inner periphery of the top slab liner substantially orthogonal to the top
slab liner, and a doughnut-shaped steel reinforcement structure on the top
slab liner, and lifting and mounting the prefabricated structure to a
position where the top slab is to be constructed; and welding a flange for
mounting a top head of the container to the container sleeve.
Preferably, the prefabricated doughnut-shaped steel reinforcement structure
has an auxiliary plate integrated therewith and located near the innermost
circumference of the doughnut-shaped steel reinforcement structure.
It is also preferred that the welding of the flange to the container sleeve
is conducted simultaneously with placement of concrete in the space which
is on the opposite side of the auxiliary plate to the flange and the
container sleeve, followed by placement of concrete in the space defined
by the auxiliary plate, the flange and the container sleeve.
According to another aspect of the present invention, there is provided a
nuclear reactor container, comprising: a bottom-equipped cylindrical
portion for containing a nuclear reactor therein; a top slab provided on
the top of the cylindrical portion and composed of a doughnut-shaped steel
reinforcement structure and concrete placed integrally with the steel
reinforcement structure, the top slab having a central bore; a sleeve
outlining in the central bore of the flange and a flange fixed by welding
to the sleeve and having an outside diameter greater than the inside
diameter of the doughnut-shaped steel reinforcement structure; and a top
head attached to the flange.
Preferably, the steel reinforcement structure has an auxiliary plate
located near the innermost circumference of the doughnut-shaped steel
reinforcement structure.
According to the invention, the flange portion is formed separately from
the sleeve and is then fixed to the sleeve by welding. In the case where
the outside diameter of the flange is greater than the inside diameter of
the doughnut-shaped steel-reinforced structure, the flange can be welded
to the sleeve after installation of the steel reinforcement structure, so
that the term of construction work can be greatly shortened.
According to the invention, it is also possible to integrate the steel
reinforcement structure of the top slab, top slab liner and the sleeve and
to install this integral structure as a unit. This eliminates the
necessity for temporary trusses and, hence, further contributes to
improvement in the efficiency of the construction work.
According to the present invention, the sleeve and the flange are split so
that the installation of the above-mentioned integral structure is
facilitated. A cylindrical auxiliary plate, while strengthening the
steel-reinforced prefabricated structure so as to prevent any deformation
of the prefabricated structure during installation of the same, also
prevents hiding the welding line between the flange and the container
sleeve by concrete, thus enabling welding and inspecting of the weld to be
executed simultaneously with the placement of concrete in a space on the
outer diameter side of the cylindrical auxiliary plate. After flange and
the container sleeve is welded, the concrete is placed in the space
between the cylindrical auxiliary plate and the container sleeve.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a prefabricated top slab steel
reinforcement structure used in an embodiment of the present invention;
FIG. 2 is a vertical sectional view of a top slab structure in an
embodiment of the nuclear reactor container of the present invention;
FIG. 3 is a flow chart illustrating an embodiment of the construction
method of the present invention;
FIG. 4 is a vertical sectional view of a top slab of another embodiment of
the present invention;
FIG. 5 is a vertical sectional view of the whole of a nuclear reactor
container made of steel-reinforced concrete;
Fig.6 is a vertical sectional view of a top slab structure of a known
nuclear reactor container; and
FIG. 7 is a flow chart illustrative of a conventional construction method;
and
FIG. 8 is a vertical sectional view of a top slab structure like that in
FIG. 4 showing the simultaneous welding and placement of concrete in the
space on the outer diameter of the auxiliary plate.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
An embodiment of the present invention will be described with reference to
FIGS. 1, 2 and 3.
Referring to FIG. 2, after setting a cylindrical liner 11, temporary posts
14 and temporary trusses 15 are placed and a top slab liner 10 is laid on
the temporary trusses 15, followed by setting of a sleeve 17 of the
nuclear reactor container. Then, the cylindrical liner 11 and the top slab
liner 10 are welded along a welding line 12. Subsequently, the top slab
liner 10 and a sleeve 17 of the nuclear reactor container are welded
together along a welding line 13. Meanwhile, a top slab steel
reinforcement structure 8 (see FIG. 1) is prefabricated on the ground
together with an auxiliary plate 19. The prefabricated top slab steel
reinforcement structure 8 is lifted and set on the top slab liner 10.
Then, a flange 16 and the sleeve 17 are welded together along a welding
line 18. This welding is conducted simultaneously with the placement of
concrete in the space on the outer diameter side of the auxiliary plate.
After examination of the welding at the welding line 18, concrete is
placed in the space defined by the integrated flange 16 and the sleeve 17,
and the auxiliary plate 19.
In an embodiment in which the top slab steel reinforcement structure 8 is
integrated with the top slab liner 10, the top slab liner 10 serves as a
reinforcer, so that the temporary trusses 15 shown in FIG. 2 can be
eliminated.
A further improvement in the efficiency of the construction work can be
attained by integrating the top slab steel reinforcement structure 8, top
slab liner 10 and the sleeve 17 of the nuclear reactor container, in
advance of the installation. An embodiment which uses such an integrated
structure is shown in FIG. 4.
Referring to FIG. 4, H-shaped steel bars 20 are laid on the upper surface
of the top slab liner 10 and are fixed to the same by welding. Then, the
steel reinforcement structure 8 is assembled on the H-shaped steel bars 20
and the lower end of the steel reinforcement structure 8 is welded to the
upper surfaces of the H-shaped steel bars 20, whereby the steel
reinforcement structure is integrated with the top slab liner 10. The
sleeve 17 and the top slab liner 10 have been welded together along a
welding line 13. In this embodiment, the top slab liner 10 functions as a
reinforcer, so that the temporary trusses 15 shown in FIG. 2 can be
eliminated.
Although each of the described embodiments employs an auxiliary plate 19
which is assembled together with the top slab steel reinforcement
structure, the use of the auxiliary plate 19 is not essential. Without the
auxiliary plate, the flange and the container sleeve must be welded before
any concrete is poured. The use of the auxiliary plate 19, however, is
preferred because the auxiliary plate stiffens the steel reinforcement
structure so as to prevent deformation of this structure when the same is
lifted for installation. The auxiliary plate also contributes to
strengthening of the built-up nuclear reactor container. Additionally, the
auxiliary plate acting as a barrier makes it possible to divide the
placement of concrete whereby welding the flange and the container sleeve
can be conducted on the inner diameter side of the auxiliary plate while
pouring concrete into a space on the outer diameter side as shown
schematically in FIG. 8.
As will be understood from the foregoing description, according to the
invention, the flange is formed separately from the sleeve and is joined
to the latter by welding. Therefore, construction of a nuclear reactor
container having a flange of a diameter greater than the inside diameter
of doughnut-shaped steel reinforcement structure can be conducted without
difficulty by welding the flange to the sleeve after installation of the
steel reinforcement structure, thus shortening the term of the
construction work. In the embodiment in which the top slab steel
reinforcement structure, top slab liner and the sleeve are integrated
beforehand, the efficiency of the construction work is further improved
because the temporary trusses can be omitted.
The installation of the above-mentioned integral structure can be
facilitated by splitting the sleeve portion and the flange portion.
The cylindrical auxiliary plate prevents the welding line between the
sleeve and the flange from being hidden by concrete so as to make it
possible to simultaneously conduct the welding and the placement of
concrete on the opposite side of the auxiliary plate. The auxiliary plate
also strengthens the steel reinforcement structure so as to prevent
deformation of this structure when the same is lifted for installation and
also contributes to strengthening of the built-up nuclear reactor
container.
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